The present invention relates generally to motion picture projectors and more particularly to a drive control mechanism for selectively actuating a motion picture projector to several operational modes and utilizing a brake mechanism to stabilize the film transporting drive assembly of the projector and to prevent film spillage.
Motion picture projectors normally include a drive control arrangement that includes a forward and reverse film transporting drive assembly and a controller assembly which is manually movable into various positions for selecting corresponding operating modes. A motion picture projector of this type is described in U.S. Pat. No. 3,952,969 which issued to J. G. Woodier on Apr. 27, 1976.
During the selection of the various projection modes and when shifting between the various operational modes, it is desirable to improve the stabilization of the film transporting drive assembly and to provide arrangements to aid in preventing film spillage. Such conditions arise when shifting the controller assembly between the fast forward and rewind modes for example.
While motion picture projectors of the prior art have provided arrangements for relatively stable film transporting such as when shifting between operational modes and these arrangements are generally suitable for their intended purpose, these arrangements are either overly complex, unreliable or are not easily adaptable to the film drive and control mechanisms of projectors currently available. Further, many of the prior arrangements do not sufficiently stabilize the film transporting drive assembly to prevent film spillage and film breakage when an operator inadvertently and rapidly shifts between search modes, fast forward and reverse for example.
In accordance with the present invention, it is a principal object to provide an improved drive control mechanism in a projector to stabilize film transporting when shifting between various operational modes and to prevent film spillage and breakage.
It is a further object of the present invention to provide a simplified and reliable drive control mechanism that utilizes a brake shoe arrangement in a projector actuator by the mode controller of the projector.
It is another object of the present invention to provide a drive control mechanism in a projector having a dual clutch drive assembly and a braking arrangement wherein the brake arrangement control member and the dual clutch control member are operated in common by a pattern of rotational and axial movements.
It is yet another object of the present invention to provide a drive control mechanism with braking action in a projector that is easily adaptable to projector apparatus and avoids one or more of the above-described disadvantages of the prior art arrangements.
These and other objects of the present invention are efficiently achieved by providing a drive control mechanism for selectively actuating a motion picture projector to several operational modes to transport film between a supply device and a take-up device that utilizes a brake mechanism to stabilize a selective driving assembly and to prevent film spillage.
The drive control mechanism is provided with a mode controller that translates various positions into predetermined axial and rotational positions and movements that is coupled through actuating members to control a dual clutch assembly driven by a unidirectional input. A brake assembly control device is also coupled to the mode controller and conditions the operation of the brake assembly.
The brake assembly is a pivotally operated dual brake shoe arrangement which is pivoted into operative contact with the dual clutch assembly wherein the brake shoe arrangement is selectively operated in and between predetermined operational modes as the brake assembly control device is axially shifted and rotated in response to the mode controller.